X-ray inspection system

ABSTRACT

An X-ray inspection system and methodology is disclosed. The system comprises a conveyor, an X-ray source that exposes an item under inspection to X-ray radiation and at least one X-ray detector that detects X-ray radiation modified by the item. The X-ray source and X-ray detector may be movable in any of first and second dimensions. The X-ray source may also be moved in a third dimension to zoom in and out on regions of interest in the item order inspection. The system further comprises a controller that controls movement of the X-ray source and X-ray detector, independently of each other, in any of collinear and different directions, to provide a plurality of X-ray views of the item at varying examination angles of the X-ray radiation. A processor coupled to the controller may be configured to receive and process detection information from the X-ray detector and to provide processed information to an operator interface. The operator interface may also receive instructions from an operator input and provide the instructions to the controller.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 10/732,581,filed Dec. 10, 2003, entitled “X-RAY INSPECTION SYSTEM,” which in turnis a continuation of application Ser. No. 10/115,443, filed on Apr. 3,2002, entitled “X-RAY INSPECTION SYSTEM,” which claims priority under 35U.S.C. § 119(e) to U.S. Provisional Application Ser. No. 60/281,117,entitled “X-RAY INSPECTION SYSTEM,” filed on Apr. 3, 2001, which isherein incorporated by reference in its entirety.

BACKGROUND

1. Field of the Invention

The invention relates to X-ray inspection systems for examination ofitems such as baggage or packages. More specifically, the inventionrelates to an X-ray inspection system and method, that utilizes X-rayradiation modified by the item under inspection to detect, for example,weapons, drugs, explosives, or other contraband.

2. Discussion of Related Art

X-ray baggage inspection systems typically operate by exposing an itemof baggage to X-ray radiation and detecting the X-ray radiation that istransmitted through or scattered from the examined baggage. Some systemshave used a single view source detector arrangement, while others haveused dual view or multi-view arrangements. The single or dual viewsystems usually scan baggage as it moves on a conveyor, using a fan orscanning pencil beam of X-ray radiation in a fixed geometry. Multi-viewsystems such as Computed Tomography (CT) systems usually perform a 360°scan of stationary baggage, and process data corresponding to absorptionof the X-ray radiation from different scan angles to reconstruct athree-dimensional image of the baggage.

At airports, the baggage inspection procedure may be divided into anumber of levels of inspection. A level one system may process baggagerapidly, such as at a targeted rate of approximately 1500 bags per hour.The level one system may be located at a first inspection station andmay inspect all baggage. The level one system may rapidly scan baggageusing some detection methodology, to eliminate non-suspicious baggage.This methodology may determine a property of materials within thebaggage, such as, for example, mass density, or effective atomic number,or may employ Compton X-ray scatter, ion mass spectroscopy, or otherdetection techniques. The number of bags that are not cleared (that arerejected) by a level one system may range from 10%-50% of the totalnumber of bags, depending on the detection methodology and threatthresholds used in the particular system.

In a multi-level system, the bags rejected by the level one system maybe automatically sent to a level two area where an operator may visuallyinspect an X-ray image of the bag. The operator may search the image ofthe bag for characteristic objects, such as weapons, wires, explosives,etc., and may attempt to determine whether a suspicious object withinthe bag may be cleared based on its obvious shape. The operator at alevel two station may clear most, but not all of the rejected bags. Theremaining baggage may be on the order of, for example, 0.1%-0.5% of theinitial stream, and may be sent to a level three inspection station. Atthe level three station, the bag may be inspected with a slowerinspection device, than a level one system, that may use a differentdetection methodology to the level one system.

One example of a level three inspection device may be a CT scanner. CTscanners are usually successful in identifying explosives inside a bagwhen the explosives are present in large amount. The CT scanner maymeasure the mass density of the examined object. The CT scanner may beset up to communicate with the level one system in order to interrogatea specific object or region of interest, that was identified in the bagby the level one system. However, CT scanners can be expensive and slow.

Another example of a device that may be used as a level three detectiondevice may be a multi-probe tomography system such as that described inU.S. Pat. No. 5,642,393, herein incorporated by reference.

On average, a level three device may tend to clear less than half of theobjects it inspects. Thus, approximately 0.05%-0.25% of the baggage mayneed to be sent to a level four area. A level four area may be definedas reconciliation of the bag with the owner, which may often bedifficult. If reconciliation is not possible, the bag may be confiscatedand additional problems may arise, such as, termination of the flightthat the bag was to be on.

While the above system can perform adequately, there is still a need fora device that may be used, for example, as a level three device that canreliably detect various explosives and other contraband having differentshapes and locations in the item under inspection.

SUMMARY OF THE INVENTION

One embodiment is directed toward an X-ray inspection system comprisingan X-ray source located at an inspection region that exposes an itemunder inspection to X-ray radiation and that is constructed and arrangedto be movable in any of the first dimension, a second dimension, and athird dimension. The system further comprises an X-ray detector locatedat the inspection region that detects X-ray radiation as modified by theitem under inspection, and that is constructed and arranged to bemovable in the first dimension and the second dimension. The systemfurther comprises a controller coupled to each of the X-ray source, theX-ray detector, that controls movement of the X-ray source in the firstand second dimensions, the X-ray detector in the first and seconddimensions, and a processor coupled to the controller that is configuredto receive detection information from the X-ray detector, to process thedetection information, and to provide processed information. Thecontroller is also configured to control movement of the X-ray sourceand the X-ray detector, independently of each other, in any of collineardirections and different directions, to provide a plurality of X-rayviews of the item under inspection at varying examination angles of theX-ray radiation.

According to another embodiment, the controller is additionallyconfigured to control movement of the X-ray source in the thirddimension so as to provide varying levels of zoom of the processedinformation to the operator interface.

According to another embodiment, the system also comprises an operatorinterface, coupled to the controller and the processor, that isconfigured to receive instructions from an operator input, to providethe instructions to the controller to control movement of any of theX-ray source, the X-ray detector and the conveyor, and that isconfigured to receive the processed information and present theprocessed information to an operator.

According to another embodiment, the processor is additionallyconfigured to process the plurality of X-ray views to create a tiledscout view of the item under inspection and to provide the tiled scoutview to the operator interface.

According to another embodiment, the processor is further configured toreceive information about the item under inspection from a remoteinspection device, and to locate a region of interest in the item underinspection based on the information received.

Another embodiment is directed toward an X-ray inspection systemcomprising an X-ray source located at an inspection region that exposesan item under inspection to X-ray radiation and that is constructed andarranged to be movable in any of the first dimension, a seconddimension, and a third dimension. The system further comprises an X-raydetector located at the inspection region that detects X-ray radiationas modified by the item under inspection, and that is constructed andarranged to be movable in the first dimension and the second dimension.The system further comprises a controller coupled to each of the X-raysource, the X-ray detector, that controls movement of the X-ray sourcein the first and second dimensions, the X-ray detector in the first andsecond dimensions, and a processor coupled to the controller that isconfigured to receive detection information from the X-ray detector, toprocess the detection information, and to provide processed information.The controller is additionally configured to control movement of theX-ray source in the third dimension so as to provide varying levels ofzoom of the processed information to the operator interface.

According to another embodiment, the controller is also configured tocontrol movement of the X-ray source and the X-ray detector,independently of each other, in any of collinear directions anddifferent directions to provide a plurality of X-ray views of the itemunder inspection at varying examination angles of the X-ray radiation.

According to another embodiment the system also comprises an operatorinterface, coupled to the controller and the processor, that isconfigured to receive instructions from an operator input and to providethe instructions to the controller to control movement of any of theX-ray source, the X-ray detector and the conveyor, and that isconfigured to receive the processed information and present theprocessed information to an operator.

A further embodiment is directed toward a high resolution X-rayinspection system comprising a high resolution X-ray source located atan inspection region that exposes an item under inspection to X-rayradiation. The high resolution source has a focal spot size that is lessthan approximately 100 m, and is constructed and arranged to be movablein any of the first dimension, a second dimension, and a thirddimension. The system further comprises an X-ray detector located at theinspection region that detects X-ray radiation as modified by the itemunder inspection, and that is constructed and arranged to be movable inthe first dimension and the second dimension, and a controller. Thecontroller is coupled to each of the X-ray source, the X-ray detector,and controls movement of the X-ray source in the first and seconddimensions, and movement of the X-ray detector in the first and seconddimensions. The system further comprises a processor that is configuredto receive detection information from the X-ray detector, to process thedetection information, and to provide processed information.

Another embodiment comprises an operator interface that is coupled tothe controller and the processor, and is configured to receiveinstructions from an operator input, to provide the instructions to thecontroller to control the movement of any of the X-ray source, the X-raydetector and the conveyor, and is configured to present the processedinformation to an operator.

Another embodiment is directed toward a method of inspecting an itemwith an X-ray system, the method comprising acts of exposing an item toX-ray radiation from an X-ray source, detecting the X-ray radiation, asmodified by the item, with an X-ray detector, processing informationprovided by the X-ray detector to provide processed information, andproviding the processed information. The method further comprises actsof moving the X-ray source in any of a first dimension and a seconddimension to expose the item to X-ray radiation at a plurality ofpositions, and moving the X-ray detector, independently of the X-raysource, in any of the first dimension and the second dimension to detectthe X-ray radiation at a plurality of positions, so as to provide theprocessed information at a plurality of examination angles.

According to another embodiment, the method further comprises an act ofmoving the X-ray source in a third dimension so as to provide varyinglevels of zoom of the processed information to the operator interface.

According to another embodiment, the act of processing the informationcomprises creating a tiled scout view of the item from X-ray imagesobtained at each the plurality of positions, and wherein the act ofproviding the processed information comprises providing the tiled scoutview to the operator interface.

According to another embodiment, the method further comprising acts ofreceiving, from a remote inspection device, information about the itemand locating a region of interest in the item based on the informationreceived.

Another embodiment is directed to a method of inspecting an item with anX-ray system, comprises acts of exposing an item to X-ray radiation froman X-ray source, detecting the X-ray radiation as modified by the itemwith an X-ray detector, processing information provided by the X-raydetector to provide processed information, and providing the processedinformation. The method further comprises acts of moving the X-raysource in any of a first dimension and a second dimension to expose theitem to X-ray radiation at a plurality of positions, moving the X-raydetector in any of the first dimension and the second dimension todetect the X-ray radiation at a plurality of positions, and moving theX-ray source in a third dimension so as to provide varying levels ofzoom of the processed information.

Another embodiment is directed to a method of inspecting an item with anX-ray system, comprising acts of exposing an item to X-ray radiationfrom an X-ray source having a focal spot size of less than approximately100 μm, detecting the X-ray radiation as modified by the item with anX-ray detector, processing information provided by the X-ray detector toprovide processed information. The method further comprises acts ofmoving the X-ray source in any of a first dimension and a seconddimension to expose the item to X-ray radiation at a plurality ofpositions, and moving the X-ray detector in any of a first dimension anda second dimension to detect the X-ray radiation at a plurality ofpositions.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are herein incorporated by reference,are not intended to be drawn to scale. In the drawings, each identicalor nearly identical component that is illustrated in various figures isrepresented by a like numeral. For purposes of clarity, not everycomponent may be labeled in every drawing. In the drawings:

FIG. 1 is an illustration of a multi-level inspection system of therelated art;

FIG. 2 is a schematic illustration of an X-ray inspection systemaccording to one embodiment;

FIGS. 3 a and 3 b are diagrams illustrating image clarity and focallength advantages and characteristics of a high resolution X-ray sourcethat may be used in the X-ray inspection system of FIG. 2;

FIG. 4 a is a perspective view of an exemplary embodiment of an X-raydetector that may be used in the X-ray inspection system of FIG. 2;

FIG. 4 b is a top plan view of the exemplary X-ray detector of FIG. 4 a;

FIG. 5 is a block diagram of one embodiment of a controller and operatorinterface that may be used in the X-ray inspection system of FIG. 2;

FIG. 6 is a schematic representation of movement of one or both of theX-ray source and X-ray detector to create a tiled scout view that may beprovided by the system of FIG. 2;

FIG. 7 is a schematic representation illustrating the movement of one orboth of the X-ray source and X-ray detector to create a tiled scout viewwhen the item under inspection is moving;

FIG. 8 is an example of an operator interface that may be used in theX-ray inspection system of FIG. 2;

FIG. 9 a is an example of an X-ray images that may be provided by theX-ray inspection system of FIG. 2.

FIG. 9 b is another example of an X-ray image that may be provided bythe X-ray inspection system of FIG. 2.

FIG. 10 is a flow diagram illustrating one embodiment of a method forlocating a region of interest in a tiled scout view of an item underinspection, based on a region of interest located in another image ofthe item; and

FIG. 11 is a schematic illustration of an X-ray inspection systemaccording to another embodiment.

DETAILED DESCRIPTION

In general, the X-ray inspection system disclosed herein can be used todetect different types of contraband (for example, weapons, drugs,money, plastic explosives, or other types of explosives) that may bepresent in items such as baggage or packages, by detecting X-rayradiation transmitted through and/or scattered from the item. However,it is to be appreciated that the X-ray inspection system is not solimited, and may be used in a number of ways, such as, non-destructivetesting of parts, and the like.

Referring to FIG. 1, there is illustrated a multi-level inspectionsystem 10 as is known in the related art. It includes a first inspectiondevice 12, which may be, for example, a level one or level two X-rayinspection system, which examines items being transported on a conveyor14. When the inspection device 12 examines an item 16 and determinesthat the item is free of any questionable regions of interest that couldcontain, for example, contraband such as drugs or explosives, the item(for example, items 16 a, 16 b), may be automatically directed by anitem director 20 in communication with the inspection device 12, toproceed further along conveyor 14. If inspection device 12 detects aquestionable region of interest within an item 16, the item director 20may direct item 16 c along conveyor 14 b to an X-ray inspection system18, which may be, for example, a level three X-ray inspection system,such as the X-ray inspection system disclosed infra. The X-rayinspection system 18 may be coupled to an operator interface 22 locatedat remote location 32, where an operator can oversee the inspectionprocess, evaluate data detected and processed by the X-ray inspectionsystem 18, and direct operation of the X-ray inspection system 18. It isto be appreciated that although the X-ray inspection system may beinterfaced for operator control, the X-ray inspection system may also beconfigured to automatically evaluate and determine whether region ofinterest in an item under inspection is cause for concern.

FIG. 2 is a schematic view of one embodiment of an X-ray inspectionsystem 24 that may be used, for example, as a level three X-rayinspection device as described above. An item under inspection 16 may betransported on a conveyor 14 to an inspection region 26. The conveyor 14may be halted so that the item under inspection 16 is stationary duringthe examination process, or it may continue moving. The movement of theitem by conveyor 14, in response to a control signal on line 25, may beunder operator control, such as via operator interface 50, or automaticcontrol by controller 40. Once the item under inspection 16 is atinspection region 26, it may be exposed to X-ray radiation from an X-raysource 28. An X-ray detector 30 may be located at the inspection region26 to detect X-ray radiation either transmitted through, or scatteredby, the item under inspection 16. In the embodiment illustrated in FIG.2, the X-ray detector 30 may be located at an opposite side of theconveyor 14 from the X-ray source 28, to detect attenuation of the X-rayradiation transmitted by the X-ray source 28 through the item underinspection 16.

The conveyor 14, the X-ray source 28, and the X-ray detector 30 may becoupled to controller 40, which may independently control movement ofthe X-ray source 28, by a control signal on line 27, in any and all of afirst (x), second (y), and third (z) dimension, may independentlycontrol movement of the X-ray detector 30, by a control signal on line29, in any and all of the first (x) and second (y) dimensions, and mayindependently control movement of the conveyor 14 in the first (x)dimension in response to a control signal on line 25. The controller 40may also control the times at which the X-ray source 28 emits X-rayradiation. The controller 40 may further be configured to receivedetection information from the X-ray detector 30 on line 35, to processthe detection information, and to provide processed information. It isto be appreciated that although one embodiment of a system for measuringan item under inspection is illustrated in FIG. 2, various alterationsand modifications readily apparent to one of skill in the art are alsowithin the scope of this disclosure even though each and everyalternative is not expressly described herein. For example, it isintended that the system of FIG. 2 can comprise an embodiment whereinthe detector 30 may be also movable in the Z dimension. It is alsocontemplated that the system of FIG. 2 may further comprise a device atthe inspection region, that may be responsive to the processor, thatrotates the item under inspection to provide up to and including a 360°rotation of the item under inspection.

The controller 40 may be coupled to an operator interface 50 which maybe configured to receive instructions from an operator, to allow theoperator to, via the controller 40 and the operator interface 50,control movement of any and all of the X-ray source 28, the X-raydetector 30, and the conveyor 14. The controller 40 may also present theprocessed information, which may be in the form of, for example, anX-ray image to the operator interface 50 to be accessed by an operator.The controller 40 and the operator interface 50 may further be coupledto a network connection 34 that allows information, such as, theprocessed information to be transmitted to, and received from, a remotelocation. A remote inspection device 104 may be located at the remotelocation. It is to be appreciated that the network connection can be anycommunication network, such as, an intranet within an airport facilityand the internet, and that the remote inspection device 104 can be anyremote device such as an operator interface remote from the system 24but within the airport facility or an operator interface at anotherairport facility.

According to one embodiment of the X-ray inspection system 24, thecontroller 14 may comprise any of a central processing unit 42, a datainterface 44, a control interface 46, and a display interface 48. Theoperator interface 50 may comprise operator controls 52 and a display54. The central processing unit 42 may be coupled to the operatorcontrols 52 so that by manipulating the operator controls 52 an operatorcan provide input signals to the central processing unit 42. The centralprocessing unit 42 may also be coupled to the control interface 46,which in turn may be coupled to actuators (not illustrated) associatedwith the X-ray source 28, the X-ray detector 30, and the conveyor 14.Control signals may be sent from the central processing unit 42 throughthe control interface 46 to the actuators via control signals on lines27, 29 and 25 to respectively control movement of the X-ray source 28,the X-ray detector 30, and the conveyor 14. The central processing unit42 may also be coupled to a data interface 44. The data interface 44 maybe configured to receive detection information from the X-ray detector30 on line 35, and to transfer it to the central processing unit 42where it may be processed before being transferred to the operatorinterface 50. The display interface 48 may also be coupled to thecentral processing unit 42 and may be configured to receive processedinformation from the central processing unit 42 and provide theprocessed information in a suitable format to the operator interface 50,for example in the form of an X-ray image. The X-ray image can bedisplayed on the display 54, for access by an operator.

It is to be appreciated that although the system of FIG. 2 isillustrated as comprising a conveyor 14, a corresponding actuator (notillustrated), and is coupled to controller 40, the system of FIG. 2 canbe provided without a conveyor and can be configured to be adapted to anexisting conveyor device. For example, where the system of FIG. 2 is tobe used at an airport already having a conveyor system, the system ofFIG. 2 can be configured to work with and interface to the existingconveyor system.

Referring to FIG. 3, according to one embodiment of the X-ray inspectionsystem, the X-ray source 28 (see FIG. 2) may be a high resolution,micro-focus X-ray source having a focal spot size 56 less thanapproximately 100 μm. In another embodiment, the high resolution X-raysource may have a focal spot size 56 that is less than approximately 20μm. In yet a another embodiment, the high resolution X-ray source mayhave a focal spot size less than approximately 12 μm. The highresolution X-ray source may be used in conjunction with a highresolution X-ray detector to provide a high resolution X-ray inspectionsystem. FIGS. 3 a and 3 b illustrate two advantages and characteristicsof a micro-focus X-ray source 28 as compared to a conventional X-raysource 36.

FIG. 3 a illustrates an effect on clarity of an X-ray image using ahigh-resolution X-ray source 28 that has a small focal spot 56 (forexample, less than 100 μm), as opposed to a conventional X-ray source 36that has a focal spot 58 size of approximately 300 μm. The magnificationand resolution of an X-ray image 38 provided by an X-ray source may bedetermined, at least in part, by the focal spot size of the X-raysource. As shown in FIG. 3 a, a smaller focal spot size 56 can result ina higher resolution, clearer image 38 of an item 16 than can be obtainedwhen the item 16 is exposed by a conventional X-ray source 36 having alarger focal spot size 58, where the sources are located the samedistance away from the item 16. The larger size of the focal spot 58 ofthe conventional X-ray source 36 may cause some cross-over of the X-rayradiation, resulting in an indistinct image 60.

FIG. 3 b illustrates a second characteristic and advantage of amicro-focus X-ray source 28. The micro-focus X-ray source 28 may have ashorter focal length 62 than the focal length 64 of the conventionalX-ray source 36. Because of this shorter focal length 62, two distancesmay be reduced, allowing, for example, for a more compact instrumentpackage. First, for an image of the same magnification, distance 66 fromthe micro-focus X-ray source 28 to image 38 may be reduced compared withthe distance 68 from the conventional source 36 to the image 70. Second,the shorter focal length 62 may allow the item under inspection 16 to beplaced closer to the X-ray source 28. Since the X-ray magnitudeincreases (is not as attenuated) as the distance from the X-ray source28 to the item under inspection 16 decreases, the microfocus X-raysource 28 may provide a greater magnitude of X-ray radiation to the item16 for an image with the same magnification as the conventional source36, and may thereby produce a sharper, clearer, and higher resolutionX-ray image. Because of the characteristics of the micro-focus X-raysource 28 discussed above, the microfocus X-ray source 28 can alsoprovide greater magnification images of the item 16. As shown in FIG. 3b the micro-focus X-ray source 28 can provide an image 72 that may be ofsignificantly greater magnification than image 70 produced by theconventional source 36 at the same distance from the source.

According to the embodiments that have been described infra, the X-raysource 28 (see FIG. 2) may be a single energy X-ray source. According toanother embodiment, the X-ray source may be a dual energy X-ray source.A dual-energy X-ray source may produce high energy X-ray radiation andlow energy X-ray radiation. A dual-energy X-ray source, X-ray inspectionsystem and methodology using the dual energy X-ray source, is disclosedin U.S. Pat. No. 5,319,547 (the '547 patent), which is incorporatedherein by reference. It is to be appreciated that the dual-energy X-raysource and system of the '547 patent can be modified as described hereinto provide an X-ray system and methodology at dual energy levels.

FIGS. 4 a and 4 b illustrate, in perspective and plan view, anembodiment of the X-ray detector 30 that may be used in the X-ray system(see FIG. 2). The X-ray detector 30 may be a radiation image detectorsuch as a PerkinElmer RID 1640. The X-ray detector 30 may be a flatpanel sensor 74 fabricated using thin film technology includingamorphous silicon on glass panels. The panel sensor 74 may be a squareimage sensing photodiode array with 1024×1024 pixels. Each pixel 76 ofthe X-ray detector array may consist of a light sensing photodiode and aswitching thin film transistor formed with the amorphous silicontechnology.

For this embodiment of the X-ray detector, the amorphous siliconphotodiodes are sensitive to visible light. This light-sensitivephotodiode array may be coupled to a scintillation material whichresponds to X-rays. When striking the scintillator, the X-rays areconverted to visible light which may be detected by the photodiodes andtransformed into electrical signals. The sensitivity of amorphoussilicon photodiodes peaks in the green light spectrum, which is wellmatched to scintillators made of a material, such as, Csl or Gd₂O₂S:Tb,which is commercially available as a LANEX® fine scintillator from, forexample, Kodak. The amorphous silicon panel itself is substantiallyimmune to damage from large doses of X-rays. This feature makes theX-ray detector array suitable for use in an inspection system, such as abaggage inspection system at an airport, where a large number of itemsare inspected at a high throughput rate, and the detector is thuscontinually exposed to X-ray radiation. It is also suitable for use incombination with a dual energy X-ray source, such as disclosed above,where the source may frequently emit high-energy and low energy X-rayradiation.

FIG. 5 illustrates an embodiment of the controller 40 and operatorinterface 50 (see FIG. 2). In this embodiment, operator interface 50 maycomprise a joystick 78 coupled the controller 40 via lines 84. In analternative embodiment, the joystick 78 may ultimately be coupled tocontroller 40 through computer 80 via line 83. The controller 40 mayalso be coupled to linear actuators 82 a-c and may effect movement ofany one of the X-ray source, the X-ray detector, and the conveyor in anyof the first, second and third dimensions. By manipulating the joystick78, the operator may provide the control signals over lines 84 tocontroller 40, which can activate the linear actuators 82 a-c to movethe conveyor to move the item under inspection in the x dimension, tomove the X-ray source in any of the x, y and z dimensions, and/or tomove the X-ray detector in the x and y dimensions to the desiredposition. It is to be appreciated that although there is illustrated oneactuator for each dimension (x, y, z) to control movement of each of theX-ray source, the X-ray detector and the conveyor, there may be providedmore than one separate actuator for each dimension and for each deviceto be moved by the actuators.

According to another embodiment, the controller 40 may receiveinformation from computer 80 operating under a process executed by thecomputer 80, to automatically move the X-ray source, the X-ray detector,and/or the conveyor to move the item under inspection, without necessaryintervention by an operator.

FIG. 6 illustrates an example movement of either one or both of theX-ray source 28 and X-ray detector 30 to create a tiled scout view thatcan be provided by the system of FIG. 2. According to one embodiment,the controller 40 may move any of the X-ray source 28, the X-raydetector 30, and the conveyor 14, to a plurality of positions in orderto create the tiled scout view 86 of the item under inspection.Referring to FIG. 6, there is illustrated an example of movement of theX-ray source and the X-ray detector, which may be moved collinearly to anumber of sequential positions, where an image is recorded at eachposition. In one embodiment, the conveyor, and thus the item, is heldstationary during the automatic inspection process and the tiled scoutview 86 may comprise an array of 30 measurements comprising five tilesin the cross-belt direction and six tiles in the down-belt direction.Each tile 88 may represent a 1024×1024 image, which may cover a 0.2m×0.2 m area on the belt. According to another embodiment of the systemof FIG. 2, the controller 40 may move the X-ray source 28 and the X-raydetector 30 independently of each other to provide a plurality of X-rayviews of the item under inspection at varying examination angles of theX-ray radiation that are provided by independent location of the X-raysource and the X-ray detector. In particular, the X-ray source and theX-ray detector can be moved independently to measure the item underinspection at numerous angles and along a plurality of planes or slicescreated by the independent locations of the source and detector.

FIG. 7 illustrates an example of movement of any or both of the X-raysource and/or the X-ray detector of FIG. 2, when the item underinspection is moving, to create a tiled scout view. It is to beappreciated that in one embodiment during the inspection process, theconveyor 14 may continue to move the item under inspection through theregion of inspection, such as, at a reduced speed, and that thismovement of the item may be accounted for in the tiling process. FIG. 7illustrates a plurality of measurements that can be used to create thetiled scout view if the item is moving during the inspection process. Atiled row of a composite image can be constructed by taking a first ⅔ ofa first frame 90 and a last ⅔ of a last frame 94 to form the left andright edges of a portion of the tiled scout view, and taking a middlethird of each intermediate frame 92 to create the interior of each tile88 of the portion of the tiled scout view. This procedure may yield atiled scout view that is five tiles in the cross-belt direction and sixtiles in the down-belt direction. The resulting composite image may be6144×5120 pixels in size. This composite image may be down-sampled bysix in both directions to yield a composite tiled scout view that may be1008×850 pixels.

FIG. 8 illustrates an example of an operator interface 96 according toone embodiment. The tiled scout view may be provided by the controllerto the operator interface for possible analysis by an operator and maybe, for example, displayed by the operator interface on computer 80 (seeFIG. 5), or on display 54 (see FIG. 2). In this embodiment of theoperator interface 96, the tiled scout view may be continuouslydisplayed in one area 98 of the display, while an image in a maindisplay area 100 may be modified by an operator. For example, at thestart of an inspection process, the initial tiled scout view may bedisplayed in the main display area 100. If an operator, or thecontroller, locates a region of interest in the tiled scout view, theoperator may select this region of interest for further inspection. Theregion of interest may then be displayed in the main display area 100,and the tiled scout view may be displayed in area 98. The operator mayfurther direct the controller, such as via the operator interface, tomove the X-ray source in the third dimension (z-dimension) closer to, orfurther away from, the item under inspection 16 (see FIG. 2) to providea zoomed image of the region of interest. The zoomed image may beobtained by moving the X-ray source closer to the item under inspection.The operator may then inspect the region of interest in greater detail.The operator may also bring the tiled scout view back to the maindisplay area 100 by manipulating an appropriate control on the operatorinterface. Various statistics and information regarding the system mayalso be displayed in a display area 102. For example, display area 102may display information such as online/offline status of screeningdevices, operator workload, number of bags screened per hour, percentageof bags rejected, etc. It is to be appreciated that another embodimentof an operator interface that may be used in the X-ray system isdescribed in detail in U.S. Pat. No. 5,870,449, which is incorporatedherein by reference.

Referring to FIGS. 9 a and 9 b, there are illustrated examples of X-rayimages that may be provided by the X-ray inspection system of FIG. 2.FIG. 9 a, illustrates an example image of a region of interest within anitem under inspection. Referring to FIG. 9 a, it is illustrated that asuspect device containing wires has been detected. FIG. 9 b illustratesan example of a zoomed image of the item of FIG. 9 a, that may beobtained by moving the X-ray source in the third dimension closer to theitem. The zoomed image may provide more detail of materials within theitem.

According to another embodiment, the controller 40 may receiveinformation about the item under inspection from a remote inspectiondevice 104 (see FIG. 2). The remote inspection device 104 may be, forexample, a level one or level two threat detection system, or aninspection device at a location different from the location of the X-rayinspection system. The controller 40 may be configured to automaticallyposition any or all of the X-ray source, the X-ray detector, and theconveyor to position the item under inspection, so as to inspect aregion of interest in the item under inspection based on the informationreceived from the remote inspection device 104, including a region ofinterest previously identified by the remote inspection device 104. Theinformation received may be an X-ray image of the item under inspectionobtained by the remote inspection device showing a region of interest inthe item, and the controller may provide the image received from theremote inspection device as well as the tiled scout view of the itemunder inspection to the operator interface 50.

According to one embodiment, an operator may compare the tiled scoutview with an image from the remote inspection device 104 to locate theregion of interest in the item under inspection. However, it is to beappreciated that the item may shift in orientation during its move fromthe remote inspection device to the present inspection region, andtherefore it may not be straightforward for the operator to locate theregion of interest in the tiled scout view. Therefore, the controller 40may also be configured to automatically compare the image obtained fromthe remote inspection device with the tiled scout view to locate theregion of interest.

Referring to FIG. 10, there is illustrated one embodiment of a processfor locating a region of interest in the tiled scout view based on apreviously located region of interest from a remote inspection device.The item may be imaged at, for example, a first level (step 110). Theitem may then be conveyed to, for example, a second level (step 112) atwhich may be located the X-ray inspection system 24 (see FIG. 2), andimaged by the X-ray inspection system (step 114). This imaging mayproduce a tiled scout view of the item. The controller may locate aregion of interest in the image provided by the first level inspectiondevice (step 116). However, the item may have been translated, rotated,or otherwise shifted in orientation during its conveyance from the firstlevel to the second level.

The X-ray inspection system may use fiduciary data regarding the item inorder to reconcile the image of the item provided by the remoteinspection device with the tiled scout view of the item. For example, an“Affine” transformation or similar transformation process, as known tothose of skill in the art, may utilize the fiduciary data to account forrotation of the item in a plane of the conveyor, translation of theitem, and magnification in the z-dimension by the system. The controllermay locate at least two fiducial points within the image from the remoteinspection device. It is to be understood that the term “fiducialpoints” are so called because they are points that remain “faithful”from one image of the item to the next, even if the item shifts inorientation between the two images. Some examples of objects in an itemthat may be suitable fiducial points may be a metal button, a metalzipper clasp, a wheel, or another small, dense object. At least twofiducial points may be used to resolve rotation and translation in thex-dimension of the item, and three fiducial points may be used toadditionally resolve translation of the item in the y-dimension.However, additional fiducial points such as up to twenty fiducialpoints, may be located in the image and used to ensure that at leastsome of these fiducial points may be located in the tiled scout view(some fiducial points that may be located in the image may be obscuredin the tiled scout view). Once the at least two fiducial points havebeen located in the image, the controller may define a geometricrelationship, such as, for example, a distance between the fiducialpoints (step 118). The controller may locate the corresponding twofiducial points in the tiled scout view of the item, and may resolve thefiducial point relationships between the image and the tiled scout view(step 124) to reconcile the image provided by the remote inspection withthe tiled scout view, and to locate the region of interest in the tiledscout view.

In an alternative embodiment, steps 116 and 118 may be performed by aremote processor associated with the remote inspection device. Accordingto such embodiment, the remote processor may create a list of fiducialdata, such as, for example, the relationships between the fiducialpoints in the image of the item (step 120), and may transmit the data tothe X-ray inspection system disclosed herein (step 122).

The controller may position the X-ray source, the X-ray detector, and/orthe conveyor to position the item and to inspect the region of interest(step 126). According to one embodiment, an operator may position any ofthe item (the conveyor), the X-ray source and X-ray detector to viewmultiple regions of interest in the item (step 128). Alternatively, thecontroller may be configured to automatically position any of the X-raysource, the X-ray detector, and the conveyor to position the item and toview multiple regions of interest in the item, based on informationreceived from the remote inspection device.

According to another embodiment, a region of interest located in an itemunder inspection may be subjected to a further, more detailed inspectionby the system of FIG. 2 in addition to the X-ray measurement. Thisfurther inspection may include one or more additional X-ray inspections,such as, a coherent X-ray scatter analysis or a Computed Laminographyscan. In this embodiment, the controller 40 (see FIG. 2) may also beconfigured to automatically position the X-ray source 28, the X-raydetector 30 and the conveyor 14, and therefore the item under inspection16, as needed for the further inspection. This additional inspection maybe done, for example, if an operator cannot clear an item based on theX-ray image alone.

Referring to FIG. 11, this embodiment of the system may further comprisean energy sensitive detector 106 a that detects X-ray radiation in apredetermined energy window that is scattered by the item underinspection. It is to be appreciated that some components of FIG. 11 areillustrated with the same reference numerals as the correspondingcomponents of the system of FIG. 2, and that the operation of thecomponents has already been discussed infra with respect to FIG. 2 andis therefore not repeated in this discussion of the embodiment of FIG.11. The energy sensitive detector 106 a may be configured to provide thecoherent scatter information to the controller 40 via line 31, which mayprocess the information and perform coherent X-ray scatter analysis. Acoherent X-ray scatter analysis may measure additional properties ofmaterials of the region of interest within the item under inspection,which may aid an operator or the system in making a decision on whetheror not the item under inspection can be cleared. According to oneembodiment, the X-ray scatter detector 106 a may be disposed in theinspection region 26 so as to detect X-ray radiation back-scattered bythe item. Alternatively, the X-ray scatter detector 106 a may bedisposed at the inspection region 26 at a different location so as todetect X-ray radiation scattered by the item under inspection at aselected angle. According to yet another embodiment, the X-rayinspection system may comprise two or more X-ray scatter detectors 106a, 106 b disposed at different locations at the inspection region 26, soas to detect X-ray radiation scattered at different angles by the itemunder inspection.

Alternatively, the X-ray source 28 and the X-ray detector 30 of theX-ray inspection system 24 may be adapted to perform a ComputedLaminography scan of the region of interest. For example, the controller40 may be configured to suitably position and control movement of any ofthe X-ray source 28, the X-ray detector 30 and the conveyor 14 to movethe item 16, to perform the Computed Laminography scan. It is to beunderstood that Computed Laminography is a measurement technique andprocess for measuring detailed X-ray images of one or more predeterminedplanar sections of an item under inspection, while not focussing onimages of other planes with the measurement. A Computed Laminographyscan may provide a better image of the item and remove clutter eitherunderlying or overlying a region of interest, thereby enabling anoperator to more clearly see the region of interest in the image. It isto be appreciated that the system of FIG. 11 can be adopted to perform acomputed Laminography scan by, for example, using the process of U.S.Pat. No. 5,490,218 herein incorporated by reference.

In another embodiment, the X-ray inspection system 24, 24′ may also beused in conjunction with a computed tomographic (CT) scanner 108 (SeeFIG. 11). The CT scanner 108 may be used to provide information aboutthe three-dimensional spatial configuration of materials within the itemunder inspection, but typically takes a long time to process each CTscan, and is therefore not ideally suited to many applications thatrequire efficient, real-time scanning of the item (such as, baggageinspection at airports). Coupling the CT scanner 108 with the X-rayinspection system 24 may increase the efficiency of the item inspection.For example, the X-ray inspection system 24 may be used to identify aregion of interest in the item under inspection that warrants a further,more detailed inspection by the CT scanner 108. Positional informationregarding the location of the region of interest in the item may beprovided by the controller 40 of the X-ray inspection system 24 to theCT scanner 108, which may then perform a CT scan on the identifiedregion of interest. Since this region of interest is typicallysignificantly smaller than the whole item under inspection, the timerequired for the CT scan may be reduced, thereby making the combinedX-ray inspection system 24, 24′ and CT scanner feasible for use in theabove-mentioned types of applications.

It is to be appreciated that with the various embodiments of X-rayinspection system disclosed herein, the item under inspection may alsobe transferred to a remote location for further inspection, shouldadditional equipment be required for the inspection. However, it shouldbe appreciated that with the system disclosed herein this should not benecessary since the X-ray inspection system is intended to providedetailed images that are sufficient to detect any contraband under mostcircumstances, and is also configured to perform most additionalscanning (if necessary) at the same location.

As was discussed infra, according to one embodiment, the X-rayinspection system 24, 24′ may include a network connection 34 (see FIG.2 and FIG. 11) that couples the system to a network such as, forexample, the Internet, a local area network, or a public telephonenetwork. It is to be appreciated that for this embodiment, thecontroller may be configured to provide the processed information, suchas X-ray images, to a remote operator interface 104 (see FIG. 1), or toreceive instructions from the remote operator interface 104, via thenetwork 34. This network allows, for example, remote operators to viewdata or images obtained by the system, to oversee or direct theinspection process, or to identify items that need be inspected whenthey arrive at the remote location. Examples of remote operators mayinclude a local police bomb squad, or a customs official at an airportdestination of the item under inspection.

Having thus described several illustrative embodiments, variousalterations, modifications and improvements will readily occur to thoseskilled in the art. Such alterations, modifications, and improvementsare intended to be within the spirit and scope of the invention.Accordingly, the foregoing description is by way of example only and isnot intended as limiting.

1. An X-ray inspection system that examines an item under inspectionlocated at an inspection region, the system comprising: an X-ray sourcelocated at the inspection region that exposes the item under inspectionto X-ray radiation, and that is constructed and arranged to be movablein any of a first dimension, a second dimension and a third dimension;an X-ray detector located at the inspection region that detects X-rayradiation as modified by the item under inspection, and that isconstructed and arranged to be movable in the first dimension and thesecond dimension; a controller coupled to each of the X-ray source andthe X-ray detector, that controls movement of the X-ray source and theX-ray detector in the first and second dimensions; a processor coupledto the controller that is configured to receive detection informationfrom the X-ray detector, to process the detection information, and toprovide processed information; wherein the controller is also configuredto control movement of the X-ray source and the X-ray detectorindependently of each other in any of collinear directions and differentdirections to provide a plurality of X-ray views of the item underinspection at varying examination angles of the X-ray radiation; whereinthe processor is further configured to receive information about theitem under inspection from a remote inspection device and to locate aregion of interest in the item under inspection based on the informationreceived.
 2. The X-ray inspection system as claimed in claim 1, whereinthe controller is additionally configured to control movement of theX-ray source in the third dimension so as to provide varying levels ofzoom of the processed information.
 3. The X-ray inspection system asclaimed in claim 1, further comprising an operator interface, coupled tothe controller and the processor, that is configured to receiveinstructions from an operator input, to provide the instructions to thecontroller to control the movement of any of the X-ray source and theX-ray detector, and that is configured to receive and to present theprocessed information to an operator.
 4. The X-ray inspection system asclaimed in claim 1, wherein the processor is configured to process theplurality of X-ray views to create a tiled scout view of the item underinspection.
 5. The X-ray inspection system as claimed in claim 4,wherein the processor is configured to create the tiled scout view of anentire item under inspection.
 6. The X-ray inspection system as claimedin claim 4, wherein the information about the item under inspectioncomprises an image, and the processor is further configured to compareat least two fiducial points in the image with at least twocorresponding fiducial points in the tiled scout view and to align theimage and the tiled scout view to locate the region of interest in thetiled scout view.
 7. The X-ray inspection system as claimed in claim 4,wherein the controller is further configured to automatically positionthe X-ray source and the X-ray detector for a further inspection of theregion of interest in the item under inspection, in response to theinformation received by the processor.
 8. The X-ray inspection system asclaimed in claim 7, further comprising an energy sensitive detectorcoupled to the processor, that detects X-ray radiation in apredetermined energy window that is scattered by the item underinspection, and wherein the processor performs a coherent scatter X-rayanalysis of the item under inspection.
 9. The X-ray inspection system asclaimed in claim 1, further comprising a conveyor constructed andarranged to move the item under inspection in the first dimension to theinspection region, and wherein the controller is further configured tocontrol movement of the conveyor in the first dimension.
 10. The X-rayinspection system as claimed in claim 9, further comprising a linearactuator responsive to the controller and coupled to the conveyor, thatmoves the conveyor in the first dimension.
 11. The X-ray inspectionsystem as claimed in claim 1, wherein the X-ray source is constructedand arranged to expose the item under inspection with a cone-shaped beamof X-ray radiation.
 12. The X-ray inspection system as claimed in claim11, wherein the X-ray source has a focal spot size of less thanapproximately 100 μm, so as to provide a high resolution X-rayinspection system.
 13. The X-ray inspection system as claimed in claim1, wherein the X-ray detector comprises a two-dimensional amorphoussilicon X-ray detector array.
 14. The X-ray inspection system as claimedin claim 2, further comprising a plurality of linear actuatorsresponsive to the controller and coupled to each of the X-ray source andthe X-ray detector, that move the X-ray source in any of the first,second and third dimensions, and move the X-ray detector in any of thefirst and second dimensions.
 15. The X-ray inspection system as claimedin claim 1, wherein the X-ray source comprises a dual-energy source thatemits low energy X-ray radiation and high energy X-ray radiation. 16.The X-ray inspection system as claimed in claim 15, wherein theprocessor is configured to determine an effective atomic number of amaterial within the item under inspection, based on a measuredattenuation through the material of the high energy X-ray radiation anda measured attenuation through the material of the low energy X-rayradiation.
 17. The X-ray inspection system as claimed in claim 1,wherein the controller is further configured to repeatedly move theX-ray source and the X-ray detector in a predetermined manner so as toperform a Computed Laminography measurement of the item underinspection.
 18. The X-ray system as claimed in claim 1, wherein theprocessor is coupled to a network and is configured to provide theprocessed information to a remote operator interface via the network.19. The X-ray system as claimed in claim 18, wherein the networkcomprises any one of the Internet, a public telephone network and alocal area network.
 20. An X-ray inspection system, comprising: an X-raysource located at an inspection region that exposes an item underinspection to X-ray radiation, and that is constructed and arranged tobe movable in any of the first dimension, a second dimension and a thirddimension; an X-ray detector located at the inspection region thatdetects X-ray radiation as modified by the item under inspection, andthat is constructed and arranged to be movable in the first dimensionand the second dimension; a controller coupled to each of the X-raysource and the X-ray detector, that controls movement of the X-raysource and the X-ray detector in the first and second dimensions; and aprocessor coupled to the controller that is configured to receivedetection information from the X-ray detector, to process the detectioninformation, and to provide processed information; wherein thecontroller is also configured to control movement of the X-ray source inthe third dimension so as to provide varying levels of zoom of theprocessed information; wherein the processor is further configured toreceive information about the item under inspection from a remoteinspection device and to locate a region of interest in the item underinspection based on the information received.
 21. The X-ray system asclaimed in claim 20, further comprising a conveyor constructed andarranged to move the item under inspection in the first dimension to theinspection region, and wherein the controller is also configured tocontrol movement of the conveyor in the first dimension.
 22. The X-raysystem as claimed in claim 20, wherein the controller is additionallyconfigured to control movement of the X-ray source and the X-raydetector independently of each other, in any of collinear directions anddifferent directions, to provide a plurality of X-ray views of the itemunder inspection at varying examination angles of the X-ray radiation.23. The X-ray system as claimed in claim 22, further comprising anoperator interface, coupled to the controller and the processor, that isconfigured to receive instructions from an operator input, to providethe instructions to the controller to control the movement of any of theX-ray source and the X-ray detector, and that is configured to receiveand to present the processed information to an operator.
 24. The X-raysystem as claimed in claim 23, wherein the processor is configured toprocess the plurality of X-ray views to create a tiled scout view of theitem under inspection, and to provide the tiled scout view to theoperator interface.
 25. A high resolution X-ray inspection systemconstructed and arranged to examine an item under inspection located atan inspection region, the high resolution X-ray inspection systemcomprising: a high resolution X-ray source located at the inspectionregion that exposes the item under inspection to X-ray radiation, theX-ray source having a focal spot size that is less than 100 μm, theX-ray source being constructed and arranged to be movable in any of afirst dimension, a second dimension, and a third dimension; an X-raydetector located at the inspection region that detects X-ray radiationas modified by the item under inspection, and that is constructed andarranged to be movable in the first dimension and the second dimension;a controller coupled to each of the X-ray source and the X-ray detector,configured to control movement of the X-ray source and the X-raydetector in the first and second dimensions; and a processor that isconfigured to: i) receive information on a region of interest in theitem under inspection from a remote inspection system; ii) provide inputto the controller whereby the controller positions the x-ray source andx-ray detector to image the region of interest; and iii) receivedetection information from the X-ray detector on the region of interest,to process the detection information, and to provide processedinformation.
 26. The high resolution X-ray inspection system as claimedin claim 25, wherein the X-ray detector comprises a two-dimensionalamorphous silicon high resolution X-ray detector array having 1024×1024pixels.
 27. The high resolution X-ray inspection system as claimed inclaim 25, further comprising a conveyor constructed and arranged to movethe item under inspection in the first dimension to the inspectionregion.
 28. The high resolution X-ray inspection system as claimed inclaim 27, wherein the controller is also configured to control movementof the conveyor in the first direction.
 29. The high resolution X-rayinspection system as claimed in claim 25, further including an operatorinterface, coupled to the controller, that is configured to receiveinstructions from an operator input, to provide the instructions to thecontroller to control the movement of any of the X-ray source and theX-ray detector, and that is configured to receive the processedinformation and to present the processed information to an operator. 30.The high resolution X-ray inspection system as claimed in claim 25,wherein the controller is additionally configured to control movement ofthe X-ray source and the X-ray detector independently of each other inany of collinear directions and different directions to provide aplurality of X-ray views of the item under inspection at varyingexamination angles of the X-ray radiation.
 31. The high resolution X-rayinspection system as claimed in claim 30, wherein the processor isconfigured to process the plurality of X-ray views to create a tiledscout view of the item under inspection.
 32. The high resolution X-rayinspection system as claimed in claim 25, wherein the controller is alsoconfigured to control movement of the X-ray source in the thirddimension so as to provide varying levels of zoom of the processedinformation.
 33. A method of operating a system for inspecting an itemhaving an x-ray source and a detector, with the relative position of thesource and detector being controllable in at least two dimensions, themethod comprising: a) displaying an image of at least a portion of theitem on an operator interface; b) receiving through the operatorinterface an indication of a region within the displayed portion of theitem; c) operating the system to obtain data on the indicated regionwherein operating the system comprises controlling the relative positionof the source and detector with respect to the item; and d) displayingon the operator interface an image of the indicated region whilesimultaneously displaying the image of at least a portion of the item.34. The method of operating a system for inspecting an item of claim 33wherein the x-ray source comprises a high resolution x-ray source havinga focal spot size of less than 100 μm.
 35. The method of operating asystem for inspecting an item of claim 33 wherein the system comprises aconveyor for moving the item and controlling the position of the sourceand detector with respect of the item comprises moving the item on theconveyor.
 36. The method of operating a system for inspecting an item ofclaim 33 wherein the position of the source and detector is controllableto change the magnification of an image of the region is formed withgreater magnification than the image of at least a portion of the item.37. The method of operating a system for inspecting an item of claim 36wherein displaying an image of at least a portion of the item comprisesdisplaying the image in a first area of a computer screen before theoperator indicates a region and in a second area of the computer screenafter the operator indicates a region and wherein the image of theindicated region is displayed in the first area.
 38. The method ofoperating a system for inspecting an item of claim 33 wherein theoperator interface comprises a joy stick.